Ch. 3 Flashcards
What is the measure of disorder in a system called?
Entropy
Which of the following represents energy in its most disordered form?
Heat energy
Because they generate order (by surviving, growing and forming complex communities), living cells defy the second law of thermodynamics.
False
Which of the following does NOT follow the first law of thermodynamics?
The use of heat to burn foodstuff inside cells
What is the origin of the energy that animals acquire by eating plants or other animals?
Sunlight
Which energy conversion characterizes photosynthesis?
Electromagnetic (light) energy → chemical bond energy
In both plants and animals, the process of “controlled burning” that extracts energy from food molecules is a process of gradual:
oxidation.
Which of the following does not describe oxidation?
The conversion of a chlorine atom to Cl-
Which of the following does describe oxidation?
The addition of oxygen atoms to a molecule and The removal of electrons from a molecule
Which of the following statements is NOT true?
Hydrogenation reactions are oxidations, and dehydrogenation reactions are reductions.
Which of the following statements IS true?
- Oxidation and reduction reactions always occur simultaneously.
- When a sugar molecule is oxidized to CO2 and H2O, O2 molecules are reduced.
Chemical reactions proceed spontaneously only in the direction that:
leads to a loss of free energy.
In thermodynamics, what does the term “free energy” refer to?
Energy that can be harnessed to do work or drive chemical reactions
Which statement about enzymes is NOT true?
Enzymes can force reactions to occur that are overall energetically unfavorable.
Which statement about enzymes IS true?
- Enzymes can speed up energetically favorable reactions.
- Enzymes can help build highly ordered structures.
What is the term for the extra energy boost required to initiate an energetically favorable reaction?
Activation energy
An enzyme can lower the activation energy of a reaction.
TRUE
.After an enzyme catalyzes a reaction, the enzyme has been consumed and cannot perform additional reactions.
FALSE
A reaction occurs spontaneously only if the change in free energy (/δ∊λταG) is:
negative.
Energetically favorable reactions are those that create disorder by decreasing the free energy of the system to which they belong.
True